Refrigerator cabinet construction

ABSTRACT

Refrigerator cabinet construction including an outer shell and a double compartment inner liner formed from a single sheet of thermoplastic material and having, in the general plane of the doors, a mullion provided between the two compartments and against which adjacent edges of the doors are adapted to seal. A portion of the hot gas line from the refrigerator condenser system extends along the rear surface of the mullion, between the adjacent side walls of the two compartments, to prevent condensation upon the exterior surface of said mullion by insuring that it is maintained at a temperature above the dew point of the ambient air. A strip of semi-flexible material of high magnetic permeability extends along the length of the mullion and has said dew point compensator tubing secured in high heat exchange relation with its rearwardly presented surface. During manufacture of the refrigerator the forwardly presented surface of said strip is maintained in intimate contact with the interior surface of the mullion through the agency of elongated magnetic means which is disposed adjacent the outer surface of the mullion during assembly of the cabinet, and particularly during foaming of insulation in the space between the inner liner and outer shell. The foamed-in-place insulation presses against the resilient strip and maintains it in good thermal relation with the interior surface of the mullion, after the magnetic means has been removed. In the resultant cabinet construction the intimate contact between the strip of material of high permeability and the interior surface of the mullion insures high heat exhange relation between the dew point compensator tube and the mullion, the strip at the same time being available as an armature, permitting use of door sealing gaskets of the magnetic type.

United States Patent [191 Franck [111 3,835,660 [451 Sept. 17, 1974Howard S. Franck, Oxford, Ohio [73] Assignee: Philco-Ford Corporation,Blue Bell,

[22] Filed: Jan. 12, 1973 [21] App]. No.: 322,976

[75] Inventor:

Primary Examiner-James C. Mitchell Attorney, Agent, or FirmHarry W.Hargis, III; Carl H. Synnestvedt; Robert D. Sanborn 7 1 ABSTRACTRefrigerator cabinet construction including an outer shell and a doublecompartment inner liner formed from a single sheet of thermoplasticmaterial and having, in the general plane of the doors, a mullionprovided between the two compartments and against which adjacent edgesof the doors are adapted to seal.

A portion of the hot gas line from the refrigerator condenser systemextends along the rear surface of the mullion, between the adjacent sidewalls of the two compartments, to prevent condensation upon the exteriorsurface of said mullion by insuring that it is maintained at atemperature above the dew point of the ambient air. A strip ofsemi-flexible material of high magnetic permeability extends along thelength of the mullion and has said dew point compensator tubing securedin high heat exchange relation with its rearwardly'presented surface.During manufacture of the refrigerator the forwardly presented surfaceof said strip is maintained in intimate contact with the interiorsurface of the mullion through the agency of elongated magnetic meanswhich is disposed adjacent the outer surface of the mullion duringassembly of the cabinet, and particularly during foaming of insulationin the space between the inner liner and outer shell. Thefoamed-in-place insulation presses against the resilient strip andmaintains it in good thermal relation with the interior surface of themullion, after the magnetic means has been removed.

In the resultant cabinet construction the intimate contact between thestrip of material of high permeability and the interior surface of themullion insures high heat exhange relation between the dew pointcompensator tube and the mullion, the strip at the same time beingavailable as an armature, permitting use of door sealing gaskets of themagnetic type.

3 Claims, 11 Drawing Figures REFRIGERATOR CABINET CONSTRUCTIONBACKGROUND A refrigerator cabinet in common use is provided with a pairof adjacent compartments, frequently arranged in side-by-side relation,each having its own door. The inner adjacent edges of the two doors sealagainst a mullion which extends throughout a major dimension of the twocompartments and in the plane of the openings thereto. These and certainother cabinets present problems arising from the fact that portions oftheir outside surface may be cooled below the dew point temperature ofsurrounding air, with resultant condensation of moisture. Frequently themullion provided between the doors tends to collect condensation andvarious means have been utilized to raise the temperature of themullion.

In certain particularly advanced refrigerators of the foregoing kind thecabinets include dual compartment inner liners fabricated from a singlesheet of thermoplastic material. In such a construction the mullion isformed integrally with the two adjacent compartments and difficultieshave arisen in effecting proper association of the dew point compensatorwith the interior surface of the mullion. An additional problem in sucha refrigerator is that the plastic mullion does not provide an armatureto which magnetic door gaskets are attracted for sealing purposes.

It is the general objective of my invention to provide an improvedmethod of cabinet fabrication which makes it possible to insuresecurement of the dew point compensator against the mullion as a resultof forces generated during the foaming of insulation in the spacebetween the plastic outer shell and inner liner, whereby to provide acabinet which is not only free from objectionable condensation upon themullion, but also enables use of magnetic sealing gaskets in conjunctionwith a mullion of plastic material. The invention also has as an objectthe provision of novel apparatus which results from practice of themethod.

SUMMARY OF THE INVENTION In achievement of the foregoing generalobjectives, the invention contemplates a novel method of fabricating arefrigerator cabinet having an integral dual compartment plastic liner.This method makes it possible to use a hot gas bypass line from thecondenser to raise the temperature of the mullion, rather than the moreexpensive and less desirable electric heaters. I provide an armature ofmagnetically permeable material, for example, vinyl impregnated withbarium ferrite, which takes the form of an extruded semi-flexible striphaving a flat surface which is disposed in contact with the interiorsurface of the mullion and is maintained in that position throughout thefoaming operation by the use of a magnet disposed exteriorly f themullion. If the external magnet is of the electro-magnetic type it maybe energized after the inner liner has been disposed within the outershell and just prior to the foaming operation. The external magnet thenattracts the magnetic strip, and the tube carried on the back surfacethereof, and holds said strip in intimate contact with the rear side ofthe mullion. After the foaming is complete the external magnet isremoved and the cured foam retains the dew point compensator tube, andthe strip which carries the same, in proper position. It is a particularadvantage of the resultant construction that the strip of magneticmaterial which extends throughout the length of the inside surface ofthe mullion is then available as an armature, cooperable with magneticdoor gaskets in sealing of the latter against the mullion.

Certain preferred embodiments of the invention have the additionaladvantage that the armature includes a tube-carrying recess havingopposed surfaces which are maintained in doubleline contact withopposite sides of the tube, thereby increasing the transmission of heatfrom the tube to the armature and thence to the mullion.

BRIEF DESCRIPTION OF THE DRAWINGS In the accompanying drawings:

FIG. 1 is a small scale perspective view of a refrigerator cabinetembodying a liner having two integrally formed compartments and aninterposed mullion of the kind with which use of the invention isparticularly advantageous;

FIG. 2 is a perspective view of apparatus shown in FIG. 1, but with themajor portion of the outer shell and insulation broken away to show thecompartment liner;

FIG. 3 is a sectional view, on a larger scale, taken through the forwardportion of the mullion of the cabinet shown in FIG. 1, and illustratingthe external magnetic means used during the fabrication process;

FIG. 4 is a somewhat diagrammatic, perspective illustration of the outershell, showing dew point compensator tubing associated therewith priorto mounting of the inner liner within said shell;

FIG. 5 is a sectional view through the outer shell and inner liner,illustrative of the way in which the shell and liner interfit, andshowing the cabinet after foaming of the insulation in the space betweensaid shell and liner;

FIG. 6 is a detail view showing a clip of a type which may be used tosupport a portion of the dew point compensator tube in association withthe intumed side flanging of the outer shell; and

FIGS. 7A through 7E are detailed sectional showings of a variety of waysin which compensator tubing may be associated with the semi-flexiblemagnetic strip which comprises the armature.

DESCRIPTION OF THE ILLUSTRATED EMBODIMENT In the accompanying drawingsthere is illustrated at 10 a double compartment refrigerator with whichthe apparatus of the invention is particularly, although not solely,usable. This refrigerator is provided with a pair of adjacentcompartments 11 and 12 disposed in sideby-side relation and each havingits own door, shown at 13 and 14 respectively. As is common in suchrefrigerators, one of the compartments, in this case compartment 11,comprises a freezing compartment, while compartment 12 is maintained atabove freezing food storage temperatures. Any suitable refrigeratingsystem, of known type, may be used to maintain the desired temperatures.The compartments are defined by an inner liner L, which appears to goodadvantage in FIGS. 2 and 5, said liner being of thermoplastic materialand being nested within an outer shell 15 which may be of metal. In arefrigerator of the kind with which the invention is especiallyconcerned, the liner compartments 11 and 12 are vacuum-formed from asingle sheet of thermoplastic material, by the use of suitable adjacentmolds and mold assist-plugs. As disclosed and claimed in US. Pat. No.3,709,968, issued Jan. 9, 1973, and assigned to the assignee of thepresent invention, the molds are moved during the vacuumformingoperation to permit close spacing of the deep drawn adjacent walls 16and 17 of the two compartments (FIG. 2). As is now known in this artthermoplastic inner liners may be disposed within outer shells, forexample the outer shell shown in the drawings at 15, and insulation 18is foamed in place between the shell and liner. As will become clear asthis description proceeds the cured foam 18 bears against the combinedarmature and dew point compensator structure characteristic of thisinvention, to hold the latter structure in high heat exchange relationwith the interior surface of a mullion 19 which bridges the gap betweensaid adjacent liner walls 16 and 17, and against which mullion the doorsof the refrigerator are adapted to seal, as appears to best advantage inFIG. 5.

As known to those skilled in this art, refrigerator cabinets,particularly cabinets provided with a plurality of doors, frequentlypresent exterior surface portions which may be cooled to temperaturesbelow the dew point temperature of the surrounding air. Objectionablecondensation results. The region of the mullion 19 is a surfaceparticularly prone to the condensation problem.

In accordance with the present invention I have provided a unique dewpoint compensator assembly of strip-like form which can readily beinserted in the narrow space between the liner walls 16 and 17, and bemaintained in close adjacency with the interior surface of the mullion19, through the agency of forces generated during the foaming ofinsulation 18. Strip-like dew point compensator support structure isshown at 20 (see particularly FIG. 3) and extends along a substantialportion of the length of the cabinet (FIG. 4). It is a feature of myinvention that this compensator structure also serves as an armatureagainst which magnetic door gaskets are attracted for sealing purposes.The doors 13 and 14 are shown in FIG. as including interior edges,disposed in adjacency when the doors are closed, which edges carrymagnetic type sealing gaskets as shown at 21.

Preferably the combined armature and compensator support structure is ofsemi-flexible material and may, for example, comprise vinyl impregnatedwith barium ferrite. The side of this strip 20, which is adapted to bedisposed away from the inside surface of the mullion 19, is providedwith elongated clamping means 20a which extends along the length of thestrip 20 and serves to clamp a portion of tubing 22 in high heatexchange relation with strip 20. Although, in one aspect of theinvention, electrical dew point compensator means may be associated withthe strip 20, it is desirable that the compensator take the form of apass of tubing which is connected in the refrigerating system (notshown) as a part of the condenser circuit. Such tubing, when maintainedin high heat exchange relation with the thermoplastic mullion, willraise the temperature of the latter sufficiently to prevent condensationof moisture on the mullion.

In accordance with the method of this invention, the outer shell 15,shown somewhat diagrammatically in FIG. 4, is provided, prior tomounting of the inner liner L, with a U-shaped loop of tubing, one legof which extends along the under surface of the left hand flangestructure 23 of the shell and the other leg of which comprises themullion compensator 22. As mentioned, the ends of this loop of tubingare coupled in the condensing side of the system.

During fabrication of the refrigerator the tubing is maintained in itsproper position with respect to the outer shell 15, through the agencyof clips shown at 24 in FIG. 6 which cooperate with the side flanging ofthe shell, and by virtue of the fact that the central unsupported pass22 thereof has clampingly associated therewith the armature strip 20, inthe manner shown in FIGS. 3 and 4. The plastic inner liner L is insertedinto the outer shell with mullion 19 overlying the associated tube andarmature and with adjacent liner walls 16 and 17 straddling the armaturestructure (FIG. 5).

The liner and shell assembly is then loaded into a suitable foamingfixture, for example a fixture similar to that illustrated and describedin the above referenced patent and magnetic means, preferably anelongated electromagnet M (FIG. 3), is moved into position to confrontand contact the exterior surface of the mullion 19. The magnet means isshown in such contact in FIG. 3, and it should be understood that, whileit may conveniently comprise an electromagnet, a strong permanent magnetmay be utilized. Regardless of the type of magnetic means, it should beunderstood that the magnet would extend along the mullion, or at leastbe effective at several spaced points therealong, and that it would bemoved translationally into contact with the mullion, as suggested by thedotted lines in FIG. 3. When this magnet is energized, it attracts thearmature strip 20 and the tubing 22 carried thereby, causing the forwardsurface of strip 20 to be held in close contact with the rear side ofthe mullion l9. Insulation is then foamed in place, in known manner,between the shell and liner, filling the space therebetween as isclearly illustrated in FIG. 5. The foamed insulation bears against therear surface of the strip 20 and the foam, after curing, retains the dewpoint compensator tube and the strip 20 in position closely contactingthe mullion. In this position, and as now will be understood, the strip20, which is of material of high magnetic permeability, is available tocooperate with the door gaskets in sealing of the latter against thethermoplastic mullion.

It is another feature of the apparatus that particularly good thermalcontact between the tubing and the armature strip is insured, since thetubing is carried within a recess which has opposed surfaces maintainingdouble line contact with the tubing, as illustrated at 25 and 26 in FIG.3. As shown in FIGS. 7A to 7B, the clamping channel shown in FIG. 3 maytake other forms. For example, in FIG. 7A, there is shown an armaturestrip 20a having a pair of opposed U-shaped tube-carrying recesses 27.This arrangement, as well as the arrangement shown in FIG. 7D, may beutilized where it is desired to have more than a single pass of tubingdisposed behind the mullion. In the apparatus of FIG. 7D tube clampingstructure 28 is generally T-shaped. FIGS. 78 and 7E show variations inwhich, respectively, double and single tube arrangements are supportedby recessing the material of the armature strip along lines extendingthroughout the length of the strip. Two such recesses appear at 29 inFIG. 7B, while a single recess is shown at 30 in FIG. 7E. Thesearrangements have the advantage of particularly good thermal contactbetween the tube and the armature structure. An additional arrangementappears in FIG. 7C, in which a double-wall curved clamp 31 substantiallysurrounds and engages the tubing.

I claim:

1. A refrigerator cabinet, comprising: an outer shell; an inner liner ofthermoplastic material nested within said outer shell, said linerpresenting a first strip of thermoplastic material having an interiorsurface facing the insulation space and an exterior surface againstwhich the refrigerator door structure is adapted to seal; a second stripof material having one surface adjacent said interior surface of saidfirst strip and another surface opposite the one surface and facing theinsulation space, said second strip being a material of high magneticpermeability; dew point compensator means extending along the recitedother surface of said second strip and secured in high heat exchangerelation therewith; and insulation foamed in place within the spacebetween the shell and liner, and bearing against said second strip tomount the same in close contact with the interior surface of said firststrip.

2. A refrigerator cabinet in accordance with claim 1, in which said dewpoint compensator means comprises refrigerant tubing, and said secondstrip includes structure defining a recess having opposed surfaces whichare clamped in double-line contact with opposite sides of said tubing.

3. A refrigerator cabinet, comprising: an outer shell; a doublecompartment liner formed from a single sheet of thermoplastic materialnested within said outer shell, said liner having, in the general planeof the compartment openings, a mullion extending between the twocompartments against which edges of compartment doors are adapted toseal; a strip-like armature of high magnetic permeability extendingalong the interior surface of said mullion and with one surface of saidarmature in close contact with the interior surface of said mullion; dewpoint compensator means secured in high heat exchange relation with theopposite surface of said strip-like armature; thermal insulation foamedin place between said shell and liner and bearing against said armatureto maintain the same in intimate contact with said mullion of saidthermoplastic inner liner in provision of high heat exchange relationbetween said dew point compensator means and said mullion through theintermediacy of said armature; and door structure carrying gasket meansof the magnetic type, the magnetic gasket means of said door structure,when the latter is in closed position, being attracted to said armaturewhereby to seal the door structure against the thermoplastic mullion.

1. A refrigerator cabinet, comprising: an outer shell; an inner liner ofthermoplastic material nested within said outer shell, said linerpresenting a first strip of thermoplastic material having an interiorsurface facing the insulation space and an exterior surface againstwhich the refrigerator door structure is adapted to seal; a second stripof material having one surface adjacent said interior surface of saidfirst strip and another surface opposite the one surface and facing theinsulation space, said second strip being a material of high magneticpermeability; dew point compensator means extending along the recitedother surface of said second strip and secured in high heat exchangerelation therewith; and insulation foamed in place within the spacebetween the shell and liner, and bearing against said second strip tomount the same in close contact with the interior surface of said firststrip.
 2. A refrigerator cabinet in accordance with claim 1, in whichsaid dew point compensator means comprises refrigerant tubing, and saidsecond strip includes structure defining a recess having opposedsurfaces which are clamped in double-line contact with opposite sides ofsaid tubing.
 3. A refrigerator cabinet, comprising: an outer shell; adouble compartment liner formed from a single sheet of thermoplasticmaterial nested within said outer shell, said liner having, in thegeneral plane of the compartment openings, a mullion extending betweenthe two compartments against which edges of compartment doors areadapted to seal; a strip-like armature of high magnetic permeabilityextending along the interior surface of said mullion and with onesurface of said armature in close contact with the interior surface ofsaid mullion; dew point compensator means secured in high heat exchangerelation with the opposite surface of said strip-like armature; thermalinsulation foamed in place between said shell and liner and bearingagainst said armature to maintain the same in intimate contact with saidmullion of said thermoplastic inner liner in provision of high heatexchange relation between said dew point compensator means and saidmullion through the intermediacy of said armature; and door structurecarrying gasket means of the magnetic type, the magnetic gasket means ofsaid door structure, when the latter is in closed position, beingattracted to said armature whereby to seal the door structure againstthe thermoplastic mullion.